1. Field of the Invention
The field of the invention relates to perforated suction rolls of the type used in machinery for manufacturing paper or related products thereof. Rolls of this type include forming cylinders, couch rolls, and the like. More particularly, this invention relates to sealing structure, which in operation of paper making machinery, is pressed against the inside surface of a suction roll while permitting sliding contact between the seal and the rotated roll. Relevant prior art, if any exists, would in applicant's opinion most likely be found in Class 162, Subclasses 48, 272, 274, 276, 279 and 367-372.
2. Description of the Prior Art
Of the prior art known to applicant, U.S. Pat. No. 2,893,487 (Dahl et al) and U.S. Pat. No. 1,867,930 (Traquair) are noted as being of possible relevance. Dahl et al. is of interest in that it relates to suction roll structure including a sealing element having a groove in its working surface, which in operation is pressed against the inside surface of a suction roll associated therewith. The groove in question in the Dahl et al. structure is zig-zag and in use communicates with several holes in the surface of the suction roll. The Traquair patent is of interest in that it discloses a suction roll device assembled from block elements having grooves on the inner surfaces thereof. While there may be some similarities between the roll structures of Dahl et al. and Traquair and that of the instant application, such similarities are believed to be superficial and this will become obvious upon a careful reading and studying of the description and drawings presented herewith.
In the normal use of perforated or drilled suction rolls, fibrous materials handled by suction rolls have a tendency to find their way through the wires on the outer surface, through the perforations and into the inner surface of the roll and if care is not taken to remove such fibrous material, it will in time accumulate in lumps to the extent that it will present an obstacle to proper sealing by pushing the seal out of contact with the roll surface.